The long term objective of this project is to explore the biochemistry and function of glycolipids, phospholipids and neutral lipids in gastrointestinal mucus in health and disease, and to provide the information on the role of mucus lipids in gastric mucosal protection. The specific goals set for the proposed period are: to define the role of covalently bound fatty acids and associated lipids in the viscoelastic, permselective and hydrophobic behavior of mucus glycoproteins along the gastrointestinal tract, and in the susceptibility of these glycoproteins to various proteases; to ascertain the extent of changes occurring in the covalently bound and associated lipids, and in the physicochemical characteristics of gastric mucus glycoprotein in stomach pathology; to assess the effect of antiulcer drugs that enhance the mucosal defense and agents affecting the integrity of mucus gel on the proteolytic susceptibility and the hydrophobic, viscoelastic, and permselective properties of gastric mucus and mucus glycoprotein; to study the effect of antiulcer drugs that enhance the mucosal defense on the acylation of mucus glycoprotein with fatty acids by gastric mucosal cells in culture; to conduct the measurements of the mucus glycoprotein fatty acyltransferase enzyme activity in fundic and antral mucosal biopsies of patients with gastric disease in order to provide an insight into the changes taking place in gastric mucus gel in stomach pathology; and to investigate the extent of changes occurring in mucus and mucosa components of gastric mucosal barrier in disease by studying in human gastric mucosal biopsies the activity of sulfotransferase enzymes responsible for sulfation of structural and secretory glycolipids.